Land reclamation, usually known as reclamation, and also known as land fill (not to be confused with a landfill), is the process of creating new land from oceans, riverbeds, or lake beds. The land reclaimed is known as reclamation ground or land fill.

In a number of other jurisdictions, including parts of the United States,[1] the term "reclamation" can refer to returning disturbed lands to an improved state. In Alberta, Canada, for example, reclamation is defined by the provincial government as "The process of reconverting disturbed land to its former or other productive uses."[2] In Oceania it is frequently referred to as land rehabilitation.

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Land reclamation can be achieved with a number of different methods. The most simple method involves filling the area with large amounts of heavy rock and/or cement, then filling with clay and dirt until the desired height is reached. The process is called "infilling"[3] and the material used to fill the space is generally called "infill".[4][5] Draining of submerged wetlands is often used to reclaim land for agricultural use. Deep cement mixing is used typically in situations in which the material displaced by either dredging or draining may be contaminated and hence needs to be contained. Land dredging is also another method of land reclamation. It is the removal of sediments and debris from the bottom of a body of water. It is commonly used for maintaining reclaimed land masses as sedimentation, a natural process, fills channels and harbors naturally.[6]

The shore of Jakarta Bay. Land is usually reclaimed to create new housing areas and real estate properties, for the rapidly expanding city of Jakarta. So far, the largest reclamation project in the city is the creation of "Golf Island", which is still ongoing.[11]

A related practice is the draining of swampy or seasonally submerged wetlands to convert them to farmland. While this does not create new land exactly, it allows commercially productive use of land that would otherwise be restricted to wildlifehabitat. It is also an important method of mosquito control.

Even in the post-industrial age, there have been land reclamation projects intended for increasing available agricultural land. For example, the village of Ogata in Akita, Japan, was established on land reclaimed from Lake Hachirogata (Japan's second largest lake at the time) starting in 1957. By 1977, the amount of land reclaimed totalled 172.03 square kilometres (66.42 sq mi).[16]

Beach rebuilding is the process of repairing beaches using materials such as sand or mud from inland. This can be used to build up beaches suffering from beach starvation or erosion from longshore drift. It stops the movement of the original beach material through longshore drift and retains a natural look to the beach. Although it is not a long-lasting solution, it is cheap compared to other types of coastal defences. An example of this is the city of Mumbai.[8]

As human overcrowding of developed areas intensified during the 20th century, it has become important to develop land re-use strategies for completed landfills. Some of the most common usages are for parks, golf courses and other sports fields. Increasingly, however, office buildings and industrial uses are made on a completed landfill. In these latter uses, methane capture is customarily carried out to minimize explosive hazard within the building.

Parts (highlighted in brown) of the San Francisco Bay were reclaimed from wetlands for urban use.

Draining wetlands for ploughing, for example, is a form of habitat destruction. In some parts of the world, new reclamation projects are restricted or no longer allowed, due to environmental protection laws. Reclamation projects have strong negative impacts on coastal populations, although some species can take advantage of the newly created area.[19]

A map of reclaimed land in Hong Kong: Grey (built), red (proposed or under development). Many of the urban areas of Hong Kong are on reclaimed land.

The State of California created a state commission, the San Francisco Bay Conservation and Development Commission, in 1965 to protect San Francisco Bay and regulate development near its shores. The commission was created in response to growing concern over the shrinking size of the bay.

Reclaimed land is highly susceptible to soil liquefaction during earthquakes,[21] which can amplify the amount of damage that occurs to buildings and infrastructure. Subsidence is another issue, both from soil compaction on filled land, and also when wetlands are enclosed by levees and drained to create Polders. Drained marshes will eventually sink below the surrounding water level, increasing the danger from flooding.

Bangladesh – about 110 square kilometres (42 sq mi) in total and has 12,000 square kilometres (4,600 sq mi) potential (8% of total area) up to 12 metres (39 ft) depth in the territorial sea area.[22]

Netherlands – about 1/6 (almost 17%) of the entire country, or about 7,000 square kilometres (2,700 sq mi) in total, has been reclaimed from the sea, lakes, marshes and swamps. The province of Flevoland has almost completely been reclaimed from the Zuiderzee.

South Korea – As of 2006, 38 percent or 1,550 square kilometres (600 sq mi) of coastal wetlands reclaimed, including 400 square kilometres (150 sq mi) at Saemangeum. Songdo International Business district, the largest private development in history, is a large-scale reclamation project built entirely on tidal mudflats.

Singapore – 20% of the original size or 135 square kilometres (52 sq mi). As of 2003[update], plans for 99 square kilometres (38 sq mi) more are to go ahead,[23] despite the fact that disputes persist with Malaysia over Singapore's extensive land reclamation works.[24]

New Zealand – significant areas of land totalling several hundred hectares have been reclaimed along the harbourfronts of Auckland, Wellington and Dunedin. In Dunedin – which in its early days was nicknamed "Mudedin" – around 2.5 square kilometres (0.97 sq mi), including much of the inner city and suburbs of Dunedin North, South Dunedin and Andersons Bay is reclaimed from the Otago Harbour, and a similar area in the suburbs of St Clair and St Kilda is reclaimed swampland. The international airports serving Auckland and Wellington have had significant reclamation for runway use.[32][33]